But many others have been registering their intent to speak out in various ways tomorrow as well. Among them:

Local tech groups including Designers and Geeks, Hacks & Hackers and the Electronic Frontier Foundation are staging a noon protest at Civic Center Plaza in San Francisco.

A similar event is being planned for outside the New York offices of Senators Charles Schumer and Kirsten Gillibrand.

Google said it will highlight its opposition in some manner on its homepage.

“Like many businesses, entrepreneurs and web users, we oppose these bills because there are smart, targeted ways to shut down foreign rogue websites without asking American companies to censor the Internet,” the company said in a statement. “So tomorrow we will be joining many other tech companies to highlight this issue on our US home page.”

Stanford’s Center for Internet and Society said it will join the blackout.

The bills aimed at online copyright infringement have sparked outrage throughout the tech industry, which argues they undermine critical legal protections that foster online innovation.

By now it’s clear the bills won’t become law in anything like their current form. The Obama Administration came out strongly against the piracy measures over the weekend, telegraphing the strong likelihood of a veto should they move forward as is. But the issue remains very much alive, as legislators work on revisions and compromise measures.

We’ll update this list as other protest plans are confirmed.

Update:

Prominent angel investor Ron Conway confirmed to the Chronicle that he’ll be speaking at the Civic Center event on Wednesday.

Update:

Firefox maker Mozilla confirmed it will: “join with other sites in a virtual strike to protest PROTECT IP Act (PIPA) and Stop Online Piracy Act (SOPA). PIPA/SOPA protect content at all costs, creating the opportunity for abuse and damaging online capabilities for all of us. Mozilla stands with this opposition and we hope the blackout of our US sites will educate people about this important issue.”

Update:

Former Senator Chris Dodd, chief executive of the Motion Picture Association of America, has called the Blackout Day a dangerous stunt.

It is an irresponsible response and a disservice to people who rely on them for information use their services. It is also an abuse of power given the freedoms these companies enjoy in the marketplace today. It’s a dangerous and troubling development when the platforms that serve as gateways to information intentionally skew the facts to incite their users in order to further their corporate interests.

A so-called “blackout” is yet another gimmick, albeit a dangerous one, designed to punish elected and administration officials who are working diligently to protect American jobs from foreign criminals. It is our hope that the White House and the Congress will call on those who intend to stage this “blackout” to stop the hyperbole and PR stunts and engage in meaningful efforts to combat piracy.